/*
 *    ConceptDriftRealStream.java
 *    Copyright (C) 2008 University of Waikato, Hamilton, New Zealand
 *    @author Albert Bifet
 
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
package moa.streams;

import java.util.Random;

import moa.core.InstancesHeader;
import moa.core.ObjectRepository;
import moa.options.AbstractOptionHandler;
import moa.options.ClassOption;
import moa.options.FloatOption;
import moa.options.IntOption;
import moa.options.Option;
import moa.options.OptionHandler;
import moa.streams.filters.StreamFilter;
import moa.tasks.TaskMonitor;
import weka.core.Attribute;
import weka.core.FastVector;
import weka.core.Instance;
import weka.core.Instances;

// Generator that adds concept drift to examples in a stream with 
// different classes and attributes. Example: real datasets
//
// Example:
//
// ConceptDriftRealStream -s (ArffFileStream -f covtype.arff) \
//    -d (ConceptDriftRealStream -s (ArffFileStream -f PokerOrig.arff) \
//    -d (ArffFileStream -f elec.arff) -w 5000 -p 1000000 ) -w 5000 -p 581012 
//
// s : Stream 
// d : Concept drift Stream
// p : Central position of concept drift change
// w : Width of concept drift change


public class ConceptDriftRealStream extends AbstractOptionHandler implements
		InstanceStream {

	@Override
	public String getPurposeString() {
		return "Adds Concept Drift to examples in a stream.";
	}
	
	private static final long serialVersionUID = 1L;

	public ClassOption streamOption = new ClassOption("stream", 's',
			"Stream to add concept drift.", InstanceStream.class,
			"generators.RandomTreeGenerator");

	public ClassOption driftstreamOption = new ClassOption("driftstream", 'd',
			"Concept drift Stream.", InstanceStream.class,
			"generators.RandomTreeGenerator");

	public FloatOption alphaOption = new FloatOption("alpha",
			'a', "Angle alpha of change grade.", 0.0, 0.0, 90.0);

	public IntOption positionOption = new IntOption("position",
			'p', "Central position of concept drift change.", 0);

	public IntOption widthOption = new IntOption("width",
			'w', "Width of concept drift change.", 1000);

	public IntOption randomSeedOption = new IntOption("randomSeed", 'r',
			"Seed for random noise.", 1);	

	protected InstanceStream inputStream;

	protected InstanceStream driftStream;

	protected Random random;
	
	protected int numberInstanceStream;

	protected InstancesHeader streamHeader;
	
	protected Instance inputInstance;
	
	protected Instance driftInstance;

	@Override
	public void prepareForUseImpl(TaskMonitor monitor,
			ObjectRepository repository) {
		
		this.inputStream = (InstanceStream) getPreparedClassOption(this.streamOption);
		this.driftStream = (InstanceStream) getPreparedClassOption(this.driftstreamOption);
		this.random = new Random(this.randomSeedOption.getValue());
		numberInstanceStream=0;
		if (this.alphaOption.getValue() != 0.0) {
			this.widthOption.setValue((int) (1/Math.tan(this.alphaOption.getValue()*Math.PI/180)));
		}

		// generate header
		Instances first = this.inputStream.getHeader();
		Instances second = this.driftStream.getHeader();
		FastVector newAttributes = new FastVector();
		for (int i = 0; i < first.numAttributes()-1; i++) {
		  newAttributes.addElement(first.attribute(i));
		}
		for (int i = 0; i < second.numAttributes()-1; i++) {
		  newAttributes.addElement(second.attribute(i));
		}


		Attribute classLabels;
		if (first.numClasses() < second.numClasses()){
			classLabels = second.classAttribute();
		} else {
			classLabels = first.classAttribute();
		}
		newAttributes.addElement(classLabels) ; 

		this.streamHeader = new InstancesHeader(new Instances(
				getCLICreationString(InstanceStream.class), newAttributes, 0));
		this.streamHeader.setClassIndex(this.streamHeader.numAttributes() - 1);
		restart();

	}


	public long estimatedRemainingInstances() {
		return -1;
	}

	public boolean hasMoreInstances() {
		return true;
	}

	public InstancesHeader getHeader() {
		return this.streamHeader;
	}
	public boolean isRestartable() {
		return ( this.inputStream.isRestartable() && this.driftStream.isRestartable() );
	}

	public Instance nextInstance() {
		numberInstanceStream++;
		double numclass = 0.0;
		double x= -4.0 * (double)(numberInstanceStream - this.positionOption.getValue())/ (double) this.widthOption.getValue();
		double probabilityDrift= 1.0 / ( 1.0 + Math.exp ( x ));
		if (this.random.nextDouble() > probabilityDrift){
			if (this.inputStream.hasMoreInstances() == false) {
				this.inputStream.restart();
			}
			this.inputInstance = this.inputStream.nextInstance();
			numclass = this.inputInstance.classValue();
		}
		else {
			if (this.driftStream.hasMoreInstances() == false) {
				this.driftStream.restart();
			}
			this.driftInstance = this.driftStream.nextInstance();
			numclass = this.driftInstance.classValue();
		}
		int m = 0; 	 
		double [] newVals = new double[this.inputInstance.numAttributes() + this.driftInstance.numAttributes()-1];
		for (int j = 0; j < this.inputInstance.numAttributes()-1; j++, m++) {
		  newVals[m] = this.inputInstance.value(j);
		}
		for (int j = 0; j < this.driftInstance.numAttributes()-1; j++, m++) {
		  newVals[m] = this.driftInstance.value(j);
		}
		newVals[m] = numclass;
   		//return new Instance(1.0, newVals);
   		Instance inst = new Instance(1.0, newVals);
		inst.setDataset(this.getHeader());
		inst.setClassValue(numclass);
		return inst;
		
	}

	public void restart() {
		this.inputStream.restart();
		this.driftStream.restart();
		numberInstanceStream=0;
		this.inputInstance = this.inputStream.nextInstance();
		this.driftInstance = this.driftStream.nextInstance();
	}

	public void getDescription(StringBuilder sb, int indent) {
		// TODO Auto-generated method stub

	}



}
